1 files changed, 34 insertions, 10 deletions
diff --git a/src/arm32/shifter/mod.rs b/src/arm32/shifter/mod.rs
index e5da07b..f658c2b 100644
--- a/src/arm32/shifter/mod.rs
+++ b/src/arm32/shifter/mod.rs
@@ -19,30 +19,50 @@
 // fero General Public License along with Pollex.
 // If not, see <https://www.gnu.org/licenses/>.
 
-use crate::arm32::{Register, Unsigned};
+use crate::arm32::Register;
 
 use core::fmt::Display;
 
 /// A shifter operand.
+///
+/// Some Arm instructions take these to minimise instruction usage.
+/// For example, the following code:
+///
+/// ```as
+/// LSL r1, r1, #2
+/// ADD r0, r1
+/// ```
+///
+/// is functionally equivalent to:
+///
+/// ```as
+/// ADD r0, r1, LSL #2
+/// ```
+///
+/// In fact, the first example will encode identically to the following:
+///
+/// ```as
+/// MOV r1, r1, LSL #2
+/// ```
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum Shifter {
- ArithmeticShiftRightImmediate { source: Register, shift: Unsigned },
+ ArithmeticShiftRightImmediate { source: Register, shift: u32 },
 
 ArithmeticShiftRightRegister { source: Register, shift: Register },
 
- Immediate { immediate: Unsigned },
+ Immediate { immediate: u32 },
 
- LogicalShiftLeftImmediate { source: Register, shift: Unsigned },
+ LogicalShiftLeftImmediate { source: Register, shift: u32 },
 
 LogicalShiftLeftRegister { source: Register, shift: Register },
 
- LogicalShiftRightImmediate { source: Register, shift: Unsigned },
+ LogicalShiftRightImmediate { source: Register, shift: u32 },
 
 LogicalShiftRightRegister { source: Register, shift: Register },
 
 RotateRightExtend { source: Register },
 
- RotateRightImmediate { source: Register, shift: Unsigned },
+ RotateRightImmediate { source: Register, shift: u32 },
 
 RotateRightRegister { source: Register, shift: Register },
 }
@@ -53,7 +73,7 @@ impl Display for Shifter {
 
 match *self {
 ArithmeticShiftRightImmediate { source, shift } => {
- write!(f, "{source}, ASR {shift}")
+ write!(f, "{source}, ASR #{shift}")
 },
 
 ArithmeticShiftRightRegister { source, shift } => {
@@ -64,8 +84,12 @@ impl Display for Shifter {
 write!(f, "#{immediate}<")
 },
 
+ LogicalShiftLeftImmediate { source, shift: 0x0 } => {
+ write!(f, "{source}")
+ },
+
 LogicalShiftLeftImmediate { source, shift } => {
- write!(f, "{source}, LSL {shift}")
+ write!(f, "{source}, LSL #{shift}")
 },
 
 LogicalShiftLeftRegister { source, shift } => {
@@ -73,7 +97,7 @@ impl Display for Shifter {
 },
 
 LogicalShiftRightImmediate { source, shift } => {
- write!(f, "{source}, LSR {shift}")
+ write!(f, "{source}, LSR #{shift}")
 },
 
 LogicalShiftRightRegister { source, shift } => {
@@ -85,7 +109,7 @@ impl Display for Shifter {
 },
 
 RotateRightImmediate { source, shift } => {
- write!(f, "{source}, ROR {shift}")
+ write!(f, "{source}, ROR #{shift}")
 },
 
 RotateRightRegister { source, shift } => {